Telescoping structure



.Wwf/ A L G O BENSON TELESCOPING STRUCTURE Flled July 26 1945 AT Tom/@YS A Patented Feb. 7, 1950 NITED STATES f ATENT OFFICE 11 Claims. 1.

This invention relates to atelescopic structure and more particularly to such a structure, such as a portable radio antenna, composed of telescoping sections which are nested together and which can be rapidly extended to provide a mast capable of being set up on any mobile or stationary support and used for sending or receiving radio messages. However, the invention is not confined to any particular use and can `also be used as a telescopic support for signal lights and for other like uses, such as tent poles.

One of the principal objects of the present invention is to provide such a telescopic structure in vwhich the sections can be quickly extended and quickly collapsed and in which the structure is securely held in its extended position `with little danger of accidental release.

Another object is to lprovide such a telescopic structure which, when extended. ls strong and will adequately resist axial, torsional and 'bending strains.

Another `object is to provide such a telescoping joint including a cross pin in which the cross pin can be located so as to impair the strength of the telescopio` joint to the least degree.

Another object is to provide a .telescopic structure which does not require tools to extend or collapse the several settiY` Another aim is tol provide such a telescopic structure which is simple `and inexpensive in construction and ,can be repeatedly extended and nested Without `objectionable Wear or deterioration.

Another aim Ais to provide a telescopic structure in which the means for holding the sections in an extended position is formed principally from the metal of the walls of the telescoping. sections thereby to reduce the .number of parts and to simplify the ,fabrication and assembly of the structure.

Another aim is to provide .such avtelescopic structure composed Vo1 metaltubes in which good electrical contact is insured `beto/.e611 .the ASeveral tubes so that it can be employed as a radio antenna.

Another object is to provide `such a telescopio structure in which the sections can be yieldingly held in their extended' position by a simple and reliable spring lrrlechan-ism `provided in each tele'- scopic join-t.

Other objects and' advantages will appear from the following .description and'drawings in whichz' Fig. 1 is a fragmentary side elevation of two sections of a telescope mast embody-lng the present invention.

Fig. 2 is a view similar to Fig. 1 showing the larger telescoping section in section.

Fig. 3 is an enlarged cross section taken on line 3.-3, Fig. 2. f

Fig.` 4 is a fragmentary vertical section taken along line 4 4, Fig. 2 in a radial plane.

Fig. 5 is a fragmentary vertical section taken on line 5-5, Fig. 1.

Fig. 6 is a View similar to Fig. 2 showing a modied form of the invention.

While the inven-tion is not confined to any particular use, it is shown as embodied in a metal antenna mast comprising a series of telescoping tubular metal sections I0, I0 which can be provided in any number and are of progressively smaller diameter so as to telescope into one another. Since the sections IU, Ill except as to size, are identical in construction, the same reference numerals are applied to the similar parts of the several sections. It will be understood that the base and tip sections (not shown) of the mast may be suitably modified to close the ends of the same and to eliminate such parts as would serve no function in these base and tip sections.

Each of the telescoping tubular sections which constitutes the main body of the mast is in the form of a tubular metal shell having a substan tially uniform wall thickness throughout and comprising .a central `cylindrical body portion ll, a cylindrical end or end sleeve I2 of reduced diameter and a cylindrical opposite end I3 of enlarged diameter Whichcan be integral with the body portion, as shown, or in the form of a separately attached collar or sleeve. The reduced cylindrical end I2 of each section is of substantial length and is of such inside diameter as to t snugly the central `body portion I I of the next smaller section II) while the enlarged. cylindrical portion I3 is of such outside diameter as to t snugly the bore of the central body portion Il of the next larger section II). The reduced cylindrical end I2 of each section is connected to the central body portion AI`I thereof by a rounded shoulder I4 formed by laterally offsetting the wall of the section. The enlarged cylindrical end I3 of each section is likewise connected to the central body portion II thereof by a rounded shoulder I5 formedbylaterally offsetting the'wall of the section, the shoulder I5 and enlarged cylindrical end I3 jointly forming an enlarged bellshaped or flared end. It will be seen that by this shape of the parts an annular chamber I t is provided `between the central body portion I I of each' section and the body portions I I of the succeeding larger and smaller sections. It will furaliadas-1 ther be seen that the ared ends or collars I3 insure alinement of the several sections in the extended condition of the mast and also serve to distribute the transverse strains at each joint.

The central body portion Il of each section Ill is provided near that end adjacent its bell-shaped enlargement I3, I with a cross pin I3 which extends diametrically therethrough and has opposite projecting ends which extend into the charner iii surrounding the section. As best shown in Fig. 3 each of these pins extends through holes I9 provided in diametrically opposite sides of the central body portion II of the corresponding section IG. Each of these pins is secured in any suitable manner, the means shown comprising a cylindrical metal plug 2i! slotted or split axially along one side, as indicated at 2i, so as to be C-shaped in cross section and provided with diametrically opposite openings 22 in its legs which receive the pin I8. By the use of a plug a greatly increased bearing area is provided for the pin I8 as compared with just the wall of the tubing itself. To hold the pin against endwise displacement and loosening it is preferably knurled, as indicated at 23. By slotting the plug 2; it can be made to conform to the slight Variations in the inside diameters of the bodies II of the tubes, these Variations being the normal production tolerances allowed in the manufacture of such tubing. Thus if the tubing is slightly oversize the plug 20 can be expanded to it the tubing tightly and, conversely, if the tubing is slightly undersize in diameter the plug can be compressed to obtain the desired lit.

in the extended position of the sections I8 the opposite projecting ends of each pin are received in a pair of bayonet slots 24 provided in diametrically opposite sides of the shoulder I4 and reduced cylindrical end I2 of the next succeeding larger section It. As best shown in Figs. 1 and 5 the axially extending entrance portion 25 cf each of these bayonet slots starts in the body portion I I of each tube and extends through the shoulder' I4 into the reduced end I2 thereof. The circumferentially extending portion 26 and reversely recessed portion 2S of each of these bayonet slots is in the reduced cylindrical end I2 of its section I0. Accordingly it will be seen that any pair of sections Iii can be extended relatively to each other until the projecting ends of the pin I8 of the smaller section strike the annular shoulder i4 leading to the reduced cylindrical end I2 of the larger section. The tWo sections I8 are then turned relative to each other until the projecting ends of the pin I8 of the smaller section find the entrance portions 25 of the diametrically opposite pair of bayonet slots 24. of the larger section. The sections I can then be drawn axially further apart, the projecting ends of the pin I8 of the smaller section traveling along the axially extending Aentrance portions 25 of the bayonet slots 24 in the larger section until the ends of this pin are in the circum'ierentially extending portions 26 thereof. The sections I0 can then be turned relative to each other to cause the ends of this pin I8 to travel along the circumferentially extending portions 2G o f these slots 24 until the ends of this pin are'disposed above the reversely recessed portions' 28 of these slots when this pin, together with the smaller section Ill, will drop into these reversely recessed portions of the bayonet slots. In this position-the two sections are reliably retained in extended position by the pin and bayonet slotV connection therebetween and hence a telescopic mast composed of suchy 4 sections will be retained in an erect position. The sections of the mast are nested by a reverse manipulation of each pair of the telescopic sections It.

The opposite ends of each pin I8 are preferably curved to conform to the exterior face of the reduced portion I2 in which it is tted, as indicated at 38, to insuremaxirnum bearing contact for supporting the pin in the bayonet slot when the mast is extended, as best shown in Fig. 3.

In order to obtain good electrical contact between each section I0 and the next succeeding larger section I8, the central body portion II of each section I8 is provided with a pair of spaced axially extending slits 38 near the bell-shaped enlargement I3, I5 thereof and in position to register with the reduced cylindrical end I2 of the next succeeding larger section when the sections are extended. The metal 3| between these slits 30 is bent outwardly and hence when the sections are extended this outwardly bent strip of metal SI is brought into firm' electrical contact with the bore of the reduced cylindrical end of the next succeeding larger section, as best illustrated in Fig. 4. It will be seen that the successive electrical contacts provided by these outwardly bent strips of metal 3| unite the mast into a unitary electrical conductor.

in order to further insure the retention of the mast in its extended condition, a spring bias can be interposed between-each pair of sections I8 and which yieldingly urges the ends of the pins I8 into the reversely extending portions 28 of the bayonet slots 24. Such a construction is illustrated in Fig. 6 in which a short ,helical compression spring 32 is interposed between the shoulder I 5 of the enlarged end I3 and the shoulder I4 of the reduced cylindrical end I 2 of the next succeeding larger section. This spring is compressed in manipulating the corresponding pin I8 into its bayonet slots 24 and to prevent binding of either end of this spring between the sections, washers 33 and 34 can be provided at opposite ends thereof, these washers loosely fitting the periphery of the central body portion I I of the smaller section and loosely fitting the bore in the central body portion I I' of the larger section. It will be seen that since the spring 32 must be cornpressed in seating the ends of the pin I8 in the bayonet slots 24, the pressure of this spring tends to retain the ends of this pin in the reversely recessed portion 28 of these slots and hence holds the mast erect and against danger of accidental collapse, the nesting of the mast, by the particular manipulation required, being initially resisted by the several springs 32.

An important feature of the invention resides in the location of the pin I8 and also the bayonet slots 24 near the center of each lap of the telescopic joint when the mast is extended. The pin I8 requires the holes 22 to be drilled in the smaller tubular section for its reception, thereby weakening the smaller tube at this point. The bayonet slots 24 also weaken the outer or larger tube. It is accordingly desirable to locate these weakened portions of both the innertube and the outer tube remote from the zones of greatest strain upon the joint. With a bending strain on the mast the extremity of the reduced portion I2 and the extremity of the enlarged portion I3 of each joint act as fulcrums and hence denne the zones of greatest strainupon the mast under bending forces.

By locating the pins I8 and.

bayonet slots 244 between these fulcrum zones, the weakened portions of,both the inner and outer tubes are removed from. these zones of greatest strain. The length or extcntof. lapin each joint, as well as the relation between thel weakened zones to the zones of greatest strain can also be controlled by the predetermined location of the pin I 8 relative to the extremity of the enlarged end I3 of the section in which it is mounted. Thus, by locating the pin B further from this extremity the` lap is increased and bringing the pin I8 closer to this extremity' decreases the lap. The desirable length of the overlap is determined by the diameter of the tubing at the joint. Roughly the overlap should be three to four times this tube diameter.

It will also bebeen that an important feature of the invention resides inthe provision of the entrance portion of each bayonet slot in the shoulder i4 with the other portions of each bayonet slot in the reduced cylindrical end l2. By this means the bayonet slots are formed directly inthe bodies of the tubes and are in position to receive the ends of the cross pins from between the chambers provided by the tubes, to releasably support the ends of the pins, and to release the ends of the cross pins back to these chambers. Further, this arrangement permits of the simple spring loading of the telescopic sections as shown in Fig. 6.

From the foregoing it will be seen that the present invention provides an extremely simple and rugged telescopic structure which is composed of few parts and at the same time is reliably held in an extended condition until intentionally nested.

I claim as my invention:

l. A telescopic structure, comprising inner` and outer slidably and rotatably intertted tubes having body portions providing between them a longitudinally extending 'chamber which surrounds one end of said inner tube, a tubular end sleeve for the body portion of said outer tube and of reduced internal diameter to lit the body portion of said inner tube, means connecting said tubular end sleeve with said body portion of said outer tube and providing an internal annular shoulder in said outer tube at the corresponding end of said chamber, and a member projecting laterally outwardly from said one end of said inner tube into said chamber, said shoulder and tubular end sleeve being recessed to receive said projecting member and releasably support said inner tube in an extended position.

2. A telescopic structure, comprising inner and outer slidably and rotatably intertted tubes having body portions providing between them a longitudinally extending chamber which surrounds one end of said inner tube, a tubular end sleeve for the body portion of said outer tube and of reduced internal diameter to t the body portion or said inner tube, means connecting said tubular end sleeve with said body portion of said outer tube and providing an internal annular shoulder in said outer tube at the corresponding end of said chamber, and a member projecting laterally outwardly from said one end of said inner tube into said chamber, said shoulder and tubular end sleeve being provided with a bayonet slot adapted to receive said projecting member and releasably support said inner tube in an extended position, said bayonet slot having its entrance portion in said shoulder, its transverse portion extending circumferentially 6. of. said tubular end4 sleeve,` and its reversely notched portion in said tubular end sleeve.

A3. A telescopic structure, comprising inner and outer sldably` and rotatably interitted` tubes having body portions providing between 4them a` longitudinally extending. chamber which surrounds one end of said inner tube, a tubular end sleeve for the body portion of said outer tube and of reduced internal diameter to t the body portion of said inner tube, means connecting said tubular end sleeve with said body` portion of said outer tube and providing an internal annular shoulder in said outer tube at the corresponding end of said chamber, a circular enlargement provided on said one end of said inner tube and tting the bore of the body portion of said outer tube. and a member projecting laterally outwardly from said inner tube adjacent said enlargement into said chamber, said shoulder and tubular end sleeve being recessed to receive-,said proj ecting member and releasably support said inner tube in an extended position.

4. A telescopic structure, comprising inner and outer slidably and rotatably interrltted tubes having body portions providing between them a longitudinally extending chamber which sur-- rounds one end of said inner tube, a tubular end sleeve for the body portion of said outer tube and of reduced internal diameter to. fit the body Dor.- tion of said inner tube, means connecting said tubular end sleeve with said body portionof saidouter tube and providing an internal annular shoulder in said outer tube atthe correspondingend of said chamber, a circular enlargement provided on said one end of said inner tube and.'

fitting the bore of the'body portion oi: said-outer tube and providing an annular shoulder on said inner tube opposing said annular shoulder of said outer tube, a member projecting laterally outwardly from said inner tube adjacent said enlargement into said chamber, said shoulder of said outer tube and said tubular end sleeve being provided with a bayonet slot adapted to receive said projecting member and releasably supportl said inner tube in an extended position, said bayonet slot having its entrance portion in said' shoulder of said outer tube, its transverse portionA extending circumferentially of said: tubular end sleeve, and its reversely notched portion-in said tubular end sleeve, and a` helical compression spring within said chamber around the body portion of said inner tube and bearing at its v'op'- posite ends against said shoulders in the extendedposition of said tubes to yieldingly hold said projecting member in said reversely' notched portion.

' 5. A telescopic structure, comprising inner and outer slidably and rotatably intertted tubes having body portions providing between them a longitudinally extending chamber which surrounds one end' of said inner tube, one end of said outer tube being reduced to nt the body portion of said inner tube and to provide an annular inwardly extending shoulder forming one end of said chamber, and a member projecting laterally outwardly from said one end of said inner tube into said chamber, said shoulder and reduced end being recessed to receive said projecting member and releasably support said inner tube in an extended position.

6. A telescopic structure, comprising inner and outer slidably and rotatably interiitted tubes having body portions providing between them a longitudinally extending chamber which surrounds one end of said inner tube, one end of said outer tube being reduced to nt the body portion of said inner tube and t provide an annular inwardly extending shoulder forming one end of said chamber, and a member projecting laterally outwardly from said one end of said inner tube into said chamber, said shoulder and reduced end being provided with a bayonet slot adapted to receive said projecting member and releasably support said inner tube in an extended position, said bayonet slot having its entrance portion in said shoulder, its transverse portion extending circumferentially of said reduced end and its reversely notched portion in said reduced end.

'7. A telescopic structure, comprising inner and outer slidably and -rotatably intertted tubes having body portions providing between them a longitudinally extending chamber which surrounds one end of said inner tube, one end of said outer tube being reduced to t the body portion of said inner tube and to provide an annular inwardly extending shoulder forming one end of said chamber, an enlarged flare provided on said one end of said inner tube and fitting the bore of the body portion of said outer tube, and a vmember projecting laterally outwardly from said inner tube adjacent to but spaced from said flare, said shoulder and reduced end being recessed to receive said projecting member and releasably support said inner tube in an extended position.

8. A telescopic structure, comprising inner and outer slidably and rotatably ntertted tubes having body portions providing between them a longitudinally extending chamber which surrounds one end of said inner tube, a tubular end sleeve for the body portion of said outer tube and of reduced internal` diameter to t the body portion of said inner tube, means connecting said tubular end sleeve with said body portion of said outer tube and providing an internal annular shoulder in said outer tube at the corresponding end of said chambenand a pin extending through said one end of said inner tube with its opposite ends projecting into said chamber, said shoulder and tubular end sleeve being recessed on opposite sides of said outer tube to receive said projecting ends of said pin and releasably support said inner tube in an extended position.

9. A telescopic structure, comprising inner and outer slidably and rotatably intertted tubes having body portions providing between them a longitudinally extending chamber which surrounds one end of said inner tube, a tubular end sleeve for the body portion of said outer tube and of reduced internal diameter to t the body portion of said inner tube, means connecting said tubular end sleeve with said body portion of said outer tube and providing an internal annular shoulder in said outer tube at the corresponding end'of said chamber, and a pin extending through said one end of said inner tube with its opposite ends projecting into said chamber, said shoulder and tubular end sleeve being provided with a pair of bayonet slots on their opposite sides adapted to receive said projecting ends of said pin, each of said bayonet slots having its entrance portion in Said shoulder, its transverse portion in said tubular end sleeve, and its reversely notched portion in said tubular end sleeve.

10. A telescopic structure, comprising inner and outer slidably and rotatably interiitted tubes having body portions providing between them a longitudinally extending chamber which surrounds one end of said inner tube, one end of said outer tube being reduced to provide an annular inwardly extending shoulder ormingone end of said chamber and an integral reduced cylindrical end tting the body portion of ,said inner tube, an enlarged flare provided on said one end of said inner tube and fitting the bore of the body portion of said outer tube, and a pin extending through said inner tube adjacent to but spaced from said flare and having its opposite ends projecting into said chamber, said shoulder and reduced end being provided with a pair of bayonet slots on their opposite sides adapted to receive said projecting ends of said pin, each of said bayonet slots having its entrance portion in said shoulder, its transverse portion inl said reduced end, and its reversely notched portion in said reduced end.

11. A telescopic structure comprising inner and outer slidably and rotatably intertted tubes, said outer tube being slotted on its opposite sides, said inner tube being provided with openings extending through its opposite sides, a pin extending through said openings and having its opposite ends projecting outwardly therefrom into said slots, and means for retaining said pin in said inner tube, comprising a plug which is C-shaped in cross section and having bores extending transversely through its legs and penetrated by said pin, said legs being capable of being distorted to t the bore of said inner tube.

v GEORGE O. BENSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 355,052 Barker Dec. 28, 1886 730,015 Halladay June 2, 1903 1,033,430 Matheson July 23, 1912 1,267,915 Shellabarger May 28, 1918 1,806,059 Hoople May 19, 1931 2,354,806 Fletcher Aug. 1, 1944 2,389,811 Oziek Nov. 27, 1945 

